Properties of isocyanurate‐type crosslinked polyurethanes

Polyurethane elastomers containing isocyanurate rings as crosslinking structure were prepared by crosslinking the prepolymers in N,N‐dimethylformamide solution with sodium cyanide catalyst. Physical properties such as gel fraction, swelling ratio, density, glass transition temperature, Young's modulus, tensile strength, and elongation at break were measured. The effects of diisocyanate structure, the degree of crosslinking, and the crosslinking structure on the properties of polyurethanes were studied. The stress–strain curves of isocyanurate‐type crosslinked polyurethanes prepared from poly(oxytetramethylene)glycol rose at lower extensions and gave higher tensile properties than those of triol‐cured and diamine‐cured polyurethanes. The observed high tensile properties were attributed to the rigid crosslinking structure of isocyanurate ring.